FIG. 3 shows a block diagram of a conventional blood corpuscle measuring and disposal system. In FIG. 3, a lower end of sample nozzle 1 may be immersed in a blood sample 2 to be measured. A predetermined quantity of blood is removed from the sample 2 by the sample nozzle 1 when a constant volume syringe 4 provides a negative pressure within the sample nozzle 1 through tube 3. The constant volume syringe 4 is a pump composed of a cylinder and a piston.
An elevating device 5 elevates the sample nozzle 1 with respect to the blood sample 2. The elevating device 5 uses a stepping motor M as a drive source. The sample nozzle 1 is raised from the sample 2 to an appointed height, as shown by arrow A in FIG. 3.
A rinsing device 6 rinses the outer circumference of the sample nozzle 1 as the sample nozzle 1 is removed from the sample 2 by elevating device 5. Thus, blood stuck to the outer circumference of sample nozzle 1 is cleaned.
A transfer device 7 horizontally transfers the sample nozzle 1 in the direction B once the sample nozzle 1 has been raised to a sufficient height above the sample 2 by elevating device 5. Once the sample nozzle 1 is horizontally moved to a position above mix cell 8, the blood within sample nozzle 1 is expelled into mix cell 8. The blood is released when the constant volume syringe 4 provides a positive pressure within sample nozzle 1 through connection tube 3.
Mix cell 8 is a vessel wherein blood is subjected to primary treatment for the measurement of blood corpuscles. In this primary treatment, a physiological solution of salt is added as a diluent to the blood, and an anticoagulant is added to the blood such as ethylene diamine tetraacetic acid (EDTA).
The primary treated blood (hereinafter referred to as the "solution") is then provided to a white blood corpuscle (WBC) cell 9 and a red blood corpuscle (RBC) cell 10 from the mix cell 8. The WBC cell 9 receives solution supplied from the mix cell 8 to subject it to further treatment for a measurement of white blood corpuscles. In the white corpuscle treatment, a blood dissolving agent is added to destroy red blood corpuscles. Additionally, cyan is added to enable the measurement of the concentration of hemoglobin in the blood sample. The Hgb concentration measurement is conducted after the measurement of the white blood corpuscle count.
A counter 11 is annexed to the WBC cell 9 for counting the number of white blood corpuscles in the solution which has been subjected to the WBC treatment. For example, an electric resistance change detecting device may be used to determine the white blood corpuscle count or concentration.
The red blood corpuscle cell 10 also receives solution from the mix cell 8. However, the red blood corpuscle cell 10 subjects the solution to a treatment including the measurement of red blood corpuscles.
Since the number of red blood corpuscles in blood is generally about 500 times that of white blood corpuscles, a secondary dilution treatment is necessary. In the secondary dilution treatment, the solution is further diluted approximately 100 times so that an error which may be due to white blood corpuscles is then within a range of an error of measurement.
A blood corpuscle counter 12 is annexed to the RBC cell 10 in order to count the number of red blood corpuscles treated in the RBC cell 10. The red blood corpuscle counter 12 uses the same electric resistance change detecting method used by white blood corpuscle counter 11. Furthermore, the mean size of the red blood corpuscles and the number of blood platelets having a volume smaller than the red blood corpuscles are measured.
An Hgb-measuring device 13 is used to measure the concentration of hemoglobin in the blood treated in WBC cell 9. The hemoglobin measuring device 13 includes a light-transmissive flow cell, which accepts and stores a quantity of solution from WBC cell 9 to hold the solution between a light source and a photodiode. Cyan is added to the solution in WBC cell 9 and combined with the hemoglobin, resulting in cyan methohemoglobin. Cyan methohemoglobin exhibits a high absorptivity for light at a wavelength of approximately 540 nanometers such that the light transmission intensity will be reduced in accordance with an increase of the concentration of the hemoglobin.
Once the various measuring operations are conducted in WBC cell 9, hemoglobin measuring device 13 and RBC cell 10, the various used waste solutions are fed into waste cell 14 for disposal. The waste cell 14 is a closed vessel which communicates with WBC cell 9, Hgb measuring device 13, and RBC cell 10 through conduits 16a, 16b and 16c provided with electromagnetic valves 15a, 15b, and 15c, respectively. The waste cell 14 is also provided with vacuum pump 17 which reduces the internal pressure within the waste cell 14 to a predetermined value.
During the processing of the solutions, the electromagnetic valves 15a, 15b, 15c are opened by valve controlling device 18 so that the solution within the WBC cell 9, RBC cell 10, and Hgb measuring device 13 are sucked into the depressurized waste cell 14 through the conduits 16a, 16b, and 16c, respectively.
The valve controlling device 18 works on a time clock. Once a predetermined time period has lapsed from the beginning of the waste collection of the treated solutions, the electromagnetic valves 15a, 15b, and 15c are closed by the valve controlling device 18. Thus, the waste solution collection is completed within a preset time estimated to be sufficient for collecting all of the treated solutions into waste cell 14.
In the above-described conventional apparatus, the time dependency is unable to account for the quantity of solution being collected from the various treatment cells. If there is less solution than estimated, the valves 15a, 15b, and 15c remain open too long. If there is more solution than estimated, the valves are not open long enough. The more beneficial case in this regard is when the valves are left open too long in order to ensure the completion of the waste collection. However, this reduces the efficiency of the operation if blood measurements are to be made continuously, one after the other.
Furthermore, it is impossible to detect a clogging of the conduits 16a, 16b, and 16c.